Headband for hearing aid transducers



Sept, 15, 1953 H. s. KNOWLES HEADBAND FOR HEARING AID TRANSDUCERS Original Filed Nov. 13, 1946 HUGH S. KNOWLES INVENTOR.

HE S A GENT Patented Sept. 15, 1953 HEADBAND FOR HEARING AID TRANSDUCERS Hugh S. Knowles, River Forest, 111., assignor to Zenith Radio Corporation, a corporation of Illinois Original application November 13, 1946, Serial N 0. 709,580. Divided and this application February 12, 1949, Serial No. 76,068

1 Claim. 1

This is a divisional application of application Serial No. 709,580, now abandoned, filed November 13, 1946, in the name of Hugh 5. Knowles for a Bone Conduction Unit.

This invention relates to an improved headband for a bone conduction transducer and more particularly to such a headband adapted to sup port a bone conduction transducer upon a users head in such a fashion as to provide optimum efficiency and comfort.

One type of headband, which has previously been used for such purposes, utilizes a resilient U-shaped member which is arranged to encompass the users head. The transducer is positioned at the extremity of one leg of the U. Thus, the pressure with which the transducer is sustained against the mastoid bone is directly dependent on the pressure which is exerted across the legs of the U. Since different users require different pressures in order to maintain the headband on the head, optimum pressure is difficult to attain for all cases.

Therefore, it is an object of this invention to provide an improved headband which sustains a bone conduction transducer against the mastoid bone of the user at a fixed pressure, independent of the pressure required to maintain the headband on the users head.

A hearing aid apparatus constructed in ac cordance with the invention includes a headband arranged to engage a users head and to provide a supporting portion. A bone conduction transducer, constructed to vibrate within a predetermined band of frequencies, is included in the apparatus, and a single resilient distort able member is mechanically connected to the supporting portion of the headband, extending beyond one termination of the headband effectively to constitute an extension thereof and supporting the transducer at its free end. The mechanical system comprising the resilient member and the transducer has a natural resonant frequency below the band of frequencies within which the transducer operates.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claim. The present invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof may best be understood by reference to the following description taken in connection with the accompanying drawing in which:

Figure 1 shows a headband embodying the present invention, and

Figure 2 shows an enlarged sectional view of the portion A of Figure 1.

Referring to Figure 1 of the drawing, the headband shown therein includes a U-shaped, head engaging, resilient strap member it having buttons or padded portions II and 19 positioned at the ends thereof. A second, elongated, resilient member i2 is slidably positioned, at one end, on member It by means of clamps l3 and M. A bone conduction unit I5 is positioned at the other end of member E2 on a support pin it.

In applying the headband to the head of a user, resilient member [0 is physically distorted in such a manner that the pressure exerted upon buttons H and i9 suits the needs of the user. The position of bone conduction transducer I5 is adjusted by sliding member it with respect to member M. Member l2 then is physically distorted in such a manner that the bone conduction transducer i5 is sustained in contact with the users mastoid bone at a pressure which provides optimum transmission efficiency of the transducer. This bone conduction transducer may, for example, be of the pressure-warning type illustrated in copending application Serial No. 560,667, filed October 27, 1944, now matured into Patent 2,459,325,, entitled Bone Conduction Unit, in the name of Hugh S. Knowles, and assigned to the same assignee as the present application.

Resilient member l2 and transducer l5 form a mechanical system to which a mechanical natural resonant frequency can be attributed. In one form of the invention, it is important that this resonant frequency occur outside of the band of operating frequencies for the transducer in order that the frequency response characteristics thereof be unaffected. It is apparent that by forming member if of small cross-sectional area as compared with its length and of a material having a relatively low modulus of elasticity, a resonant frequency below that of the lowest operating frequency for the transducer can be attained. It is equally apparent that by proper construction of resilient member 52, a natural resonant frequency for the mechanical system can be attained which is above that of the highest operating frequency for transducer l5.

Figure 2 shows in detail the portion A of Figure 1 which includes clamps l3 and Hi. There are also shown rivets l1 and [8 which permanently fasten member I2 to clamps l3 and I4, respectively. The clamps individually encompass member 10 which is free to slide therein and with respect to member l2. Member [0 is maintained at any selected position with respect to member 12 since clamps I3 and [4 are constructed to grasp the members I0 and I2 into close frictional engagement therewith.

It may be seen that the arrangement of Figure 1 provides a headband which maintains a bone conduction transducer in operative position with optimum pressure irrespective of the pressure needed to maintain the headband on the head of the user. Also, this feature reduces the tendency of a transducer 15 to crawl off the mastoid bone.

The frequency response characteristic for the transducer depends on contact pressure. Thus, by providing a uniformly compliant connection afiording constant pressure between"'the"transducer and the users head the desired frequencyresponse characteristic can be maintained.

While a particular embodiment of the pres'ent invention has been shown and described, it is apparent to those skilled in theart that changes and modifications may be made-without departing from this invention in its broader aspects, and therefore, the raimlin the appended'claimis to cover all such-changes andmodifications as fall within the true spiritand-scope of this invention.

I claim:

Hearing aid apparatus including, a headband arranged to engage a users head and to provide a supporting portion; a bone conduction transducer constructed to vibrate within a predeterminedband of frequencies; and a single'resilient distortable member mechanically connected to said supporting portion of said headband, ex-

tending beyond one termination of said headband e'fie'c'tiv'ely to constitute an extension thereof, and supporting said transducers at its free end, the

mechanical system comprising said resilient mem- :beriand.saidtransducer having a natural resonant frequency "below said band of frequencies.

HUGH S. KNOWLES.

References Cited in the file of this patent UNITED STATES PATENTS 

